Transmitting data between two sets of information processing equipment usually is accomplished through a communication protocol. UART is a commonly used communication protocol. In the event that the two sets of information processing equipment have different serial transmission communication interfaces, line connection and data transmission between these two information processing equipments have to resort an interface transformation function provided by the interface receiver/transmitter.
The receiver/transmitter has many combinations depending on the interfaces. The receiver/transmitter for the Ethernet port RJ-45 and serial transmission port RS-232 is frequently used. At present this type of receiver/transmitter does not have a status display function. When error or malfunction occurs, users do not know whether the UART functions normally. Hence users have to check individually to find the problem or causes of malfunction. This is time-consuming and not desirable nowadays.